Detection of pulsation from Swift J0513.4-6547 with Fermi/GBM
ATel #2023; Mark H. Finger (USRA), Elif Beklen (METU)
on 18 Apr 2009; 01:45 UT
Credential Certification: Dr. Mark H. Finger (Mark.Finger@msfc.nasa.gov)
Subjects: Binary, Transient, Pulsar
Pulsations from the recently discovered accreting pulsar
Swift J0513.4-6547 in the LMC (H. A. Krim et al. ATEL #2011) have been detected
in the Fermi/GBM rates between 2009 March 1 and March 28.
Pulse searches were made for several multi-day intervals covering
January 30 to April 15. The searches included both trial frequencies
near the 36.66 mHz (27.28 s period) RXTE measurement (ATEL #2011),
and trial frequency rates in the range expected for accreting
pulsars near Eddington luminosity. The intervals with detections
were:
Time Range Epoch Frequency Frequency Rate
(MJD) (MJD) (mHz) (1E-12 Hz/s)
54819.0-54897.0 54893.984 36.59407(13) 48(2)
54897.0-54902.0 54899.339 36.62742(18) 102(5)
54904.6-54908.5 54906.509 36.67029(15) 30(3)
54908.5-54912.5 54910.552 36.67429(13) -8(3)
54912.5-54918.0 54915.296 36.66989(13) -6(3)
These times, frequencies, and frequency rates are barycentric. A plot may be seen at
http://gammaray.nsstc.nasa.gov/gbm/science/pulsars/lightcurves/swiftj0513_fig1.png
The pulsed flux (mean-minimum 12-25 keV) reached 15 mCrab between March 18 and March 22, giving
a lower limit to the luminosity of 7E+37 erg/cm^2 s. The frequency rate in the second
detection interval is consistent with a pulsar accreting from a disk near the
Eddington rate. The negative frequency rates in the last two intervals are likely due
to Doppler shifts from the (unknown) binary orbit.
GBM Pulsar Project
